The present invention relates to the field of water supply systems for buildings.
The problem of burst water supply pipes and flooding of buildings has been recognized in prior art patents. In U.S. Pat. No. 4,848,389 issued to Pirkle, the feature of providing electrical control to shut off the water main supply with a first valve and draining the pipes in a building with a second valve in a TEE joint, to prevent freezing and bursting of the pipes is disclosed. These actions can be in response to thermostat sensing of potentially freezing temperatures. See also White, U.S. Pat. No. 4,730,637 in col. 7 and its abstract. The prior art also teaches sensing whether the pipes were freezing and then draining them. It is desired to provide a relatively simple, rugged inexpensive system for performing the above described function in a residential home, which need not employ relatively complex systems such as those using thermostats, or those using sensors to detect freezing, and that any homeowner could operate merely by actuating a single conspicuously located switch away from the intimidating electrical control panel upon departing from the home for an extended period of time, particularly during the winter months. It is also desired to provide a system that reduces damage due to heat failure triggered by power outages and that is not affected adversely by power surges which are commonplace in many areas.
A single master switch easily actuated by an unskilled homeowner positioned at the top of the cellar stairs for example, controls a master relay, which in turn causes a solenoid actuated water supply valve to remain open and a solenoid actuated drain valve to remain closed. When the homeowner leaves the home for an extended period, the master switch in the lower winter mode position is opened to arm the system and de-energize the master relay to in turn shut off the water supply valve and open the drain valve in the TEE joint to drain water from the pipes throughout the house. Upon returning home, the master switch is closed, a reset button is pressed, and the master relay is again energized to close the drain valve and open the main water supply valve. The master relay can also shut off the water heater, and the water pump if present, during the extended absence of the homeowner, thus saving on fuel bills. Since the pipes are drained, there is less of a need to keep the water heater operating to deter freezing of the pipes which could otherwise burst.
However, should the homeowner forget to arm the system by opening the master switch when its xe2x80x9conxe2x80x9d switch position is in the lower xe2x80x9cwinterxe2x80x9d mode, the pipes could freeze and burst requiring expensive pipe replacement and repair of the home due to flooding damage. This damage is often caused by an electrical power interruption which could shut down the heating system hastening an expensive pipe burst freeze-up condition. Electrical heating systems and certain electrically actuated heating plants are particularly susceptible. An important feature of the invention is to sense the power interruption, however brief, and cause the system to be enabled or armed just as if the homeowner had remembered to open the master switch upon leaving the home for the extended period. Optionally, a timer may be desired to eliminate the enabling effect of extremely brief power interruptions. The power interruption de-energizes the master relay to shut off the main water supply and drain the system for an extended period until the home owner returns and presses a reset button to restore normal operation. This involves the fail-safe re-energization of the relay only upon homeowner operation of the reset button upon his return, and restoration of power during his absence will not re-energize the master relay as its latching circuit remains disabled. The use of relatively complex thermostats for controlling the master relay can thus be avoided. Also, straightforward use of thermostats could turn the supply and drain valve on and off several times during temperature fluctuation cycles, in contrast with the fail safe feature of the invention, which in turn could drastically increase flooding, caused by the drain valve opening several times, to greatly increase water damage. If the valves open and close several times with the power going off and on, not only would the cellar flood, more damage could occur in the interior of the house, if there had been a freeze in a pocket of water in the interior living portion of the house.
The simple switch/master relay arrangement of the invention is useful even where freezing is not a threat and particularly where a second home is abandoned for an extended period. Pipe bursting flooding, not caused by freezing, is prevented. Also, vandals could open water valves in the home producing flooding. An optional xe2x80x9cnon-winterxe2x80x9d mode position of the master switch can be used to bypass the failsafe feature to turn the master relay on and off during each power interruption. The xe2x80x9calways onxe2x80x9d or xe2x80x9cnon-winterxe2x80x9d upper master switch xe2x80x9conxe2x80x9d position can be used when the freezing concern is not present. If there is a power failure, the system would automatically reset without having to push the reset button. If people were to have an automatic sprinkler for their lawn or garden for example, they might want to leave the water on during the week and would want to negate the requirement to push the reset button.